Hello friends! Today we will build an intelligent energy-saving demonstration using an Arduino Uno, two doorway sensors, an LCD and controlled loads. The idea is to count completed entries and exits, then switch the model room's loads according to that count. The interesting part is not simply turning a relay on. We need to recognize direction, handle an interrupted crossing, avoid counting the same person repeatedly and decide what to do when the count becomes uncertain. We will develop those rules before looking at the complete program. This is a controlled educational demonstration. Two narrow beams cannot reliably count a crowd or guarantee that a real room is empty. We will use low-voltage demonstration loads and make the limitations visible rather than treating an imperfect counter a ...
Hello friends! Today we will design and examine a buzzer circuit in Proteus ISIS. We will use a logic input, an optocoupler and a transistor to control a powered buzzer, then look at the changes needed before using the idea in hardware. A buzzer is useful for indicating a timer event, a button press or a fault. The first design decision is whether the selected sounder contains its own oscillator or requires an alternating drive signal. Applying DC works for an active buzzer, but does not produce a continuous tone from every passive transducer. The original simulation images remain in this tutorial. We will explain their active-low behavior while correcting several details that a simulation alone can hide, including LED current, transistor bias and optocoupler pin mapping. Figure: Historica ...
